Entry guide for seamless tube plug rolling mills



June 10, 1952 A. F. KRITSCHER 2,599,847

ENTRY GUIDE FOR SEAMLESS TUBE PLUG ROLLING MILLS Filed Feb. 9, 1950 3 Sheets-Sheet l FIEJL- v Imam/02: mwem f (9/50/59,

$4"? i i 5 7mg June 10, 1952 A. F. KRITSCHER ENTRY GUIDE FOR SEAMLESS TUBE PLUG ROLLING MILLS Filed Feb. 9, 1950 5 Sheets-Sheet 2 lawentar; AWMHI fi'Ke/Umflz A. F. KRITSCHER June 10, 1952 3 Sheets-Sheet 3 Filed Feb. 9, 1950 a w a w M 4 v m K X HH nn w hlnl irill ma A Patented June 10, 1952 ENTRY GUIDE FOR SEAMLESS TUBE PLUG RQLLING MILLS Andrew F. Kritscher, Pittsburgh, Pa., assignor to National Tube Company, a corporation of New J ersey Application February 9, 1950, Serial No. 143,250

6 Claims. 1

Th s nvent en. r tes o mpr e in an cess ry tor the us e l n mill used in the manuiacture. of seamless tubes. More specifically it is improved entry guide for starting e tub b an s be een the m ll ll nd r he mandrel a i held h h b n in proper p siti h he ful le h' h advances into mill Pass Plus, roll ng m ls ha e h r ore been p vided with inlet or entry guides in the form of swel ed eenn h Q he y t u stru ith een ersirs threa l t along a central horizontal plane, The upper half is supported on the. r giment he up 1.011 o 3.1 so as to be liited therewith and thus avoid interreoe wi h the ret rn Qt the l d b k w e. will ass s op ned ie stripping th blank from the mandrel bar. The diameter and shape of the bore of the guide are fixed. The shape and diameter of the blanks vary somewhat howver, and th gu de is thu a ble f exerting on all o them. he rm ripp action u r to hold them in proper relation'to the mill pass, The blanks are slightly oval in section after the t ass nd it o h d rml with the longer axis vertical, will turn down or tilt to one side.

This, may result in twisting of the tube, uneven rounding up and the formation of ridges on the interior of the wall of the finished pipe.

I have invented a novel entry guide for plug roliing mills which overcomes the aforementioned objections to the conventional inlet cannon and is characterized by further novel features and advantages thereover which will be particularly enumerated hereinafter. My improved guide comprises a pair oi spaced housings disposed side-by-side, each having a pair of vertical guide rollers iournaled therein, and supported adjacent the mill pass ior adjusting movement toward and from each other. Ifhe housings and the rollers therein are divided along a horizontal plane through the center of the pass but vertical shafts on which the rollers are journaled extend through both the upper and lower portions of the rollers and housings, thus serving to hold the separate portions of each housing and its rollers in proper assembled relation. The upper portions of the housings and rollers are suspended from the lower bearing chocks of the upper roll of the mill so as to move therewith when they are lifted to open the pass for stripping a rolled blank from e m ndr r- A fni-l understanding of the invention may be obtained from the following detailed description and explanation which refer to the accompanying V drawings illustrating the present preferred embodiment. In the drawings,

Figure 1 is a vertical section through the rolls of a plug rolling mill showing my improved guide in operative position relative thereto;

Figure 2 is an end elevation showing an entering pipe blank in section, the mill rolls and housings being omitted;

Figure 3 is a vertical transverse section taken along the plane of line IIIIII of Figure 1; and Figure 4 is a plan view with parts omitted and parts in section along a horizontal plane through the center of the pass.

Referring in detail to the drawings, Figure 1 shows my improved entry guide, indicated generally at [0, in operative relationto a plugrolling mill having upper and lower rolls H "and I2. The lower roll is journaled in chocks l3 positioned at the bottom of windows [.4 in spaced housings l5. The upper roll is journaled between upper and lower chocks l6 and I! slidable in the windows. The mill proper is shown only in outline but the usual screws and counterbalance (not shown) are provided for adjusting the upper roll. This roll is raised, of course, after a tube blank haspassed through the mill, to permit the blank to be stripped from the usual mandrel bar.

The entry guide It comprises a pair of housings i 8 and i9 disposed side-by-side which together define a guide throat for an entering tube "blank such as indicated at 20. The housings l8 and [9 are identical but of opposite hand so a detailed description of one will sufiice. The housing 18 includes separate upper and lower portions i6 and 18 The upper portion has an inverted hook 2 I extending upwardly therefrom "cheek portion 26 is formed on the inner end of the housing alongside the tongue 25. The lower portion 13 of the housing is supported on rest bars 2! and 25' extending between and secured to the mill housings l5 and is slidably secured in place thereon by a spline 29.

By virtue of the construction described thus far, the lower portions of the housings are supported in fixed position during operation of the mill but the upper portions I3 move upwardly with the upper roll when lifted to permit a tube blank to be stripped from the mandrel bar after passing through the mill.

A pair of vertical grooved rollers 30 and 3i are journaled in each of the housings l8 and 19. The two pairs of rollers together define the actual guiding pass and are the only portions of the guide structure which engage the tube blank when the latter has been started through V the mill, as illustrated in Figure 3. The, individual rollers are split transversely each being composed of separate upper and lower portions 30 30 3N and 3| lying on opposite sides, respectively, of a horizontal plane through the center line of the roll pass. The upper portions of the rollers are mounted to move with the upper portions 18* and 19 of the housings while the lower portions 39 and 3 l of the rollers rest on the lower housing portions 18* and [9 and always remain at a fixed elevation. The lifting of the upper roll of the mill thus serves to open up the pass through the entry guide rollers as well as that through the mill. 7

For suspending the upper roller portions 30 and 3| and rotatably mounting both the upper and the lower roller portions 30* and 3 l vertical shafts 32 are inserted through aligned bores in the upper and lower portions of each of the housings l8 and [9. The shafts are held in place by securing pins 33 threaded horizontally into the upper housing portions l8 and l9 and entering transverse slots in the peripheries of the shafts (see Figures 2 and 4). Each shaft has a shoulder 34 (see Figure 3) intermediate the length thereof serving as a thrust bearing to support the upper roller portions 30 or 3H. The lower ends of the shafts are slidable in the lower housing portions l8 and 9 permitting the free rise and fall of the upper housing portions 18 and l9 with the upper mill roll II.

A screwshaft 35 having right-hand and lefthand threads at its opposite ends is threaded through tapped holes in the lower housing portions I8 and [9 Rotation of the shaft thus causes the housings to move toward or away from each other depending on the direction of rotation. A tie bolt 36 extends through the upper housing portions 18* and Ill to prevent outward movement thereof on passage of a tube blank through the guide and relieve the shafts 32 of a bending load which would be caused by such movement. The nuts on the tie bolt, of; course, are backed oif when the housings are to be adjusted away from each other and then turned down to the proper extent when the desired adjustment has been effected. The screwshaft is provided with lock nuts to secure it in adjusted position against the efiects of shock, vibration and the like. During adjustment of the lower housing portions l8 and l9 by screwshaft 35, the upper housing portions l3 and I9 are, of course, correspondingly adjusted because the shafts 32 prevent relative horizontal movement between the upper and lower portions of each housing while permitting vertical movement of the upper' portion relative to the lower.

In operation, the housings l8 and [9 of the entry guide are adjusted laterally of the center line ofthemill' pass so that the rollers 30 and 3| not only'exert a gripping action but actually effect a slight deformation of the blank as it passes therethrough. It should be understood that, in the normal operation of a plug rolling mill'equipped with a previously known guide, the blank is substantially circular in section when it first enters the mill but, after the first pass, has a slight oval section with its major axis horizontal resulting from the shape of the: roll pass. It is then turned through 90 after being stripped from the mandrel bar and before: entering the mill for the second pass. The set-- ting of the guide rollers just explained thus causes the blank entering the mill pass for the first time to have a slightly oval section with. its major axis vertical, as shown in Figure 2, whichit has had heretofore only after the first pass through the mill.

After the first pass of the blank through the guide and. the mill, the lifting of the upper mill roll raises the upper portions I8 and 19 of the guide housings and the upper portions 30 and 3| of the rollers, to facilitate stripping of the blank from the mandrel bar and its return to starting position. On the second pass, the blank having been brought to slightly oval section by the first pass is nevertheless firmly engaged by the guide rollers and held with its major axis vertical, as in the first pass, whereby turning down or tilting of the major axis toward one side or the other is prevented. The slight shaping effect of the guide rollers on the tube blank in the first pass permits a long blank to be rolled Y without turning on its own axis in either direction as sometimes occurs when a conventional guide is employed.

In addition to the principal advantage of the improved roller guide in maintaining the blank more accurately in proper position for entry intothe mill pass than is possible with solid guides, the roller guide also obviates the difliculty of the solid guide by positively gripping the tube blank, holding it in a straight line and permitting a uniform amount of work to be done thereon by the mill, especially in the second pass. Since the only portions of the guide having contact with the blank after the latter has started through the mill are the rollers themselves, the wear on the parts is reduced to a minimum. The rollers are adjustable to accommodate a range of blank sizes which conventional solid guides are incapable of doing. A

series of rollers having grooves with differing tendency thereof to squeeze the blank to a slightly oval section with its major axis vertical for the initial pass through the mill is also advantageous because additional work is then done on the blank by the mill pass which, as already pointed out, is oval-shaped with its major axis horizontal.

A further advantage of the invention is that no change in the setting of'the guide is necessary to permit return of the blank therethrough by the stripper rolls without contact with the guide rollers, even though the rolling of the blank has altered its shape so that the major axis is horizontal instead of vertical. The lifting of the blank by the stripper rolls causes it to clear the lower guide rollers While the lifting of the upper mill roll raises the upper guide rollers out of the way, thus preventing any scoring of the blank by the guide rollers as a result of the shift in the positions of the major and minor axes means suspending the upper portion of each roller from the upper portion of its housing whereby said pass may be opened by upward movement of said upper housing portions.

2. The apparatus defined by claim 1 characterized by said housing-suspending means including a transverse bar, the upper portions of the housings being slidable on said bar, and means supporting the lower portions of the housings for sliding movementparallel to said bar.

3. The apparatus defined by claim 1 characterized by means for adjusting the housings toward and from each other, and a tension member holding said housings against separation.

4. The apparatus defined by claim 3 characterized by said adjusting means being a screwshaft threaded through corresponding portions of the housings and said member being a tie bolt extendin through other corresponding portions.

5. A roller guide for a rolling mill comprising a pair of housings disposed side-by-side, each housing including separate upper and lower portions, fixed means supporting the lower portions of the housings, vertically movable means suspending the upper portions of the housings, a vertical shaft depending from the upper portion of each housing into the lower portion thereof, rollers journaled on said shafts cooperating to define a pass adapted to guide a tube entering the mill, each roller including separate upper and lower portions and means suspending the upper portion of each roller from the upper portion of its housing, the lower portion of each roller resting on the lower portion of its housing.

6. A rolling-mill guide comprising a pair of spaced housings each including a relatively fixed lower portion and an upper portion separate from and movable vertically relative to the lower portion, means for suspending the upper housing portions and moving them vertically relative to the lower portions, a vertical shaft carried by one portion of each housing and extending into the other portion thereof, a guide roller on each shaft composed of upper and lower portions, and means suspending the upper. portions of the guide rollers from the upper portions of the housings, respectively, so they will move vertically therewith, whereby the upper and lower roller portions .form a pass adapted snugly to fit a tube entering the mill when the upper roller portions are in lowermost position, and upward movement of the upper roller portions opens said pass permittin free return of the tube.

ANDREW F. KRITSCHER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,452,740 Jacobs Apr. 24, 1923 1,783,148 Gorham Nov. 25, 1930 2,012,074 Smith Aug. 20, 1935' 2,353,289 Bennewitz July 11, 1944 

